The coordinated assault in Jakarta by a team of suicide bombers and gunmen follows a pattern seen in Mumbai in 2008 and in Paris last November, notes Reuters.

Gen. Karnavian identified the ringleader of the attackers as Bahrun Naim, an Indonesian currently in Syria. He said Mr. Bahrun had been sentenced to prison in Indonesia in 2012 for offenses involving illegal possession of firearms and explosives.

Other countries in Southeast Asia are also on alert for potential expansion by Islamic State, which has sought to gain affiliates outside its Middle East base of operations.

The New York Times quotes an Indonesian political analyst as saying that the government has not done enough in recent years to quell radical Islam. However, Ms. Jones noted that while Indonesia has seen a spike in the number of violent plots over the past six months, “none of it is a reaction to domestic politics.”

“It’s a desire to prove that jihadi groups are still alive and well in Indonesia and are committed to carrying out the ISIS agenda,” she said.

The vast majority of Indonesia’s 250 million citizens practice a moderate form of Islam and there are sizeable minorities of Christians, Hindus, and Buddhists.

But moderate and hard-liner Islamists, some espousing violence, have in recent years been engaged in an internal struggle, with Islamic State making inroads. Until now, most of the militant violence had been limited to low-level assaults on police and was blamed on a resurgent Jemaah Islamiyah, a Southeast Asian affiliate of Al Qaeda.

That group carried out the 2002 Bali bombing, which left 202 people dead, mostly foreigners on vacation. Prior to Thursday’s attack, the last major act of terrorism was in 2009, when two hotels were bombed. Those attacks were blamed on a splinter group from Jermaah Islamiyah.

Indonesian authorities had been successful in breaking up many of the groups involved in these attacks, but Thursday’s assault could signal a new phase.

Indonesian President Joko Widodo said in a televised address Thursday, “Our nation and our people should not be afraid… We will not be defeated by these acts of terror. I hope the public stays calm.”